Attachment 14991 Details for Bug 13859 – patch for 4.10 cherry-picked from master

[patch] patch for 4.10 cherry-picked from master

0001-lib-Make-fd_load-work-for-non-regular-files.patch (text/plain), 2.54 KB, created by Andrew Bartlett on 2019-03-26 04:55:27 UTC

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Creator: Andrew Bartlett

Created: 2019-03-26 04:55:27 UTC

Size: 2.54 KB

patch

obsolete

>From e66342c537343770cd574105c57e6cf725be7f71 Mon Sep 17 00:00:00 2001
>From: Volker Lendecke <vl@samba.org>
>Date: Thu, 21 Feb 2019 18:37:08 +0100
>Subject: [PATCH] lib: Make fd_load work for non-regular files
>
>Follow-up to
>
>https://lists.samba.org/archive/samba/2018-September/217992.html
>
>and following. This also fixes a small and very theoretical race: Between the
>fstat and the read call the file size might change. This would make us fail on
>potentially legitimate files.
>
>This is more complex and probably slower, but looking at the use cases I don't
>think the speed matters.
>
>BUG: https://bugzilla.samba.org/show_bug.cgi?id=13859
>
>Signed-off-by: Volker Lendecke <vl@samba.org>
>Reviewed-by: Andrew Bartlett <abartlet@samba.org>
>
>Autobuild-User(master): Andrew Bartlett <abartlet@samba.org>
>Autobuild-Date(master): Tue Mar 26 04:43:40 UTC 2019 on sn-devel-144
>
>(cherry picked from commit ac487bf4d04c9771ada1ca7eeb9dac4e5fe34185)
>---
> lib/util/util_file.c | 63 +++++++++++++++++++++++++++++++++++++++-------------
> 1 file changed, 48 insertions(+), 15 deletions(-)
>
>diff --git a/lib/util/util_file.c b/lib/util/util_file.c
>index 926eda240f6..29c0be91b6b 100644
>--- a/lib/util/util_file.c
>+++ b/lib/util/util_file.c
>@@ -168,30 +168,63 @@ load a file into memory from a fd.
> **/
> _PUBLIC_ char *fd_load(int fd, size_t *psize, size_t maxsize, TALLOC_CTX *mem_ctx)
> {
>-	struct stat sbuf;
>-	char *p;
>-	size_t size;
>+	FILE *file;
>+	char *p = NULL;
>+	size_t size = 0;
>+	size_t chunk = 1024;
>+	int err;
>+
>+	if (maxsize == 0) {
>+		maxsize = SIZE_MAX;
>+	}
> 
>-	if (fstat(fd, &sbuf) != 0) return NULL;
>+	file = fdopen(fd, "r");
>+	if (file == NULL) {
>+		return NULL;
>+	}
> 
>-	size = sbuf.st_size;
>+	while (size < maxsize) {
>+		size_t newbufsize;
>+		size_t nread;
> 
>-	if (maxsize) {
>-		size = MIN(size, maxsize);
>-	}
>+		chunk = MIN(chunk, (maxsize - size));
> 
>-	p = (char *)talloc_size(mem_ctx, size+1);
>-	if (!p) return NULL;
>+		newbufsize = size + (chunk+1); /* chunk+1 can't overflow */
>+		if (newbufsize < size) {
>+			goto fail; /* overflow */
>+		}
> 
>-	if (read(fd, p, size) != size) {
>-		talloc_free(p);
>-		return NULL;
>+		p = talloc_realloc(mem_ctx, p, char, newbufsize);
>+		if (p == NULL) {
>+			goto fail;
>+		}
>+
>+		nread = fread(p+size, 1, chunk, file);
>+		size += nread;
>+
>+		if (nread != chunk) {
>+			break;
>+		}
> 	}
>-	p[size] = 0;
> 
>-	if (psize) *psize = size;
>+	err = ferror(file);
>+	if (err != 0) {
>+		goto fail;
>+	}
> 
>+	p[size] = '\0';
>+
>+	if (psize != NULL) {
>+		*psize = size;
>+	}
>+
>+	fclose(file);
> 	return p;
>+
>+fail:
>+	TALLOC_FREE(p);
>+	fclose(file);
>+	return NULL;
> }
> 
> /**
>-- 
>2.11.0
>

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vl: review+

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Attachments on bug 13859: 14991